Abrasive tool



July 14, 1942- A. FIELD 2,290,098

ABRAS IVE" TOOL Filed July 22, 1940 IN VEN TOR A L BE 2T FELD /PM ff-.4%-

A TTORNEYS.

ABY

Patented July 14, 1942 l 25mini UNITED STATES PATENT 'OFFICE Albert Field, payton, ohio Application July 22,1940, serial No. 346,826

3 Claims.

The present invention relates to abrasive tools employed for polishing or finishing metal, rubber and plastic materials and particularly dental plates and the like, composed of such materials; and an abrasive element kfor use in connection with such tools, as well as a method and apparatus for making such elements.

It is an object of the present invention to provide an abrasive cone as a part of the tool of the type described, which is adaptable to use with a mandrel for attachment either to a lathe or drill chuck depending upon the desired use to which the deviceA is to be put.

Another'object of the invention is to provide` an abrasive cone composed of a single rolled strip of flexible abrasive material, provided with a central bore, wherein one end of said cone is comparatively unyielding to provide a firm4 bearing for attachment to a mandrel or the like, and wherein the opposite or Working end of said cone has a. certain flexibility or resil- Yiency whereby abrading contact of said working end of the cone with material to be finished thereby will not cause gouging thereof.

Another object of the invention is to provide an abrasive tool of simple construction comprising mandrel and abrasive cone elements in which the cones may be easily and quickly attached to the mandrel for rm inter-locking connection therewith so as to enable quick replacement of the 'cones as necessary in the use of the tool, and in which the mandrel and cone elements are so formed that their coop-v erative relation produces an abrasive tool, the working end of which may be firmly, though yieldingly, engaged with articles to be abradingly finished thereby.

In the employment of the invention herein disclosed, the abrasive tool comprises a mandrel having a tapered portion provided with a tapered thread for inter-locking connection with the non-yielding end vof the abrasive cone, said mandrel also having a Vbearing portion so formed as to extend a considerable distance into the abrasive cone to stiien the same While permitting yieldability of the working end of the One of the problems involved in providing an abrasive cone having the attributes aforementioned, and composed of a single strip of abrasive material, is that of rolling said material into a tight cone in which the rolled layers of the same are adhesively secured together with suiiicient adhesiveness to permanently maintain the s'trip in such tightly rolled yconical condition. f

One factor entering into this problem is that the abrasive material, such as emery cloth, of which said cones may conveniently be made, comprises a smooth surface towhich glue does not readily adhere, and a rough abrasive surface which does not readily cohesively engage said smooth surface, so that when glue or other adhesive material is applied to the smooth surlface of the strip as it is being rolled into the cone, the superimposed layers of the strip are not caused to adhere together with suiilcient tightness to positively prevent the cones from becoming unrolled in use.

To overcome this problem the present invention contemplates the novel expedient consisting of so treating one edge of the abrasive strip as to break down a portion of the abrasive surface thereat, while at the same time roughening the inner smooth surface of such strip in the same region.

In accordance with the disclosure herein, the foregoing result may be accomplished by the use of a perforating device which is caused to operate on the abrasive strips by first engaging the rough or abrasive surface of the strips to break down said surface in the region of contact, and then passing through the strip to break outwardlyj the material thereof from the smooth surface to provide slightly ragged protrusions of said material from said smooth surface.

The method yof making the abrasive element contemplates not only the breaking down of portions of the abrasive surface of the strip and the roughening of portions of the non-abrasive surface, but, as well, the application of adhesive to the strip while it is being rolled tightly into its nal cylindrical form.

Other objects, advantages and features of novelty of the invention will appear more fully as the description thereof progresses in conjunction with the drawing, in which:

Figure 1 is a'view showing the embodiment of myinvention with the abrasive cone assembled upon the mandrel.

Figure 2 is a view showing the mandrel alone.

Figure 3 is a View showing the abrasive strip before it is rolled into the cone.

description of the invention, the numeral I indi-v cates generally a strip of abrasive material such as sandpaper, emery cloth, or the like, emery cloth being preferred for the purposes hereof.

The abrasive strip I has an abrasive surface 2 provi material applied thereto, and its opposite surface d by the sand, emery, or like abrasive 3 is that of the cloth, paper, fabric, or other material composing the body of the strip, constituting a comparatively smooth surface.

It will be noted that the opposing edges 4 and 5 of the abrasive strip I are not parallel, the edge -5 being cut at somewhat of an angle to the edge ing end 'l of the cone are inwardly stepped, as

indicated at 8 in Figure 4. This isto enable the `cone as it becomes worn in use to continually just described, adhesive is applied to the surface 3 adacent the free edge 2| of the strip I to secure the samevto the underlying layer of said present a protruding narrow edge at its working end. l

The term cone as used herein refers to an abrasive strip rolled to form an abrasive element of the nature disclosed herein. As shown in th drawing it is more or less cylindrical in general configuration and somewhat conical at its ends. Beforfl the strips I are'rolled into their -final conical formation, indicated in Figure 1, the area adjacent the edge 4 is operated upon to, break down the abrasive material at spaced points, such as indicated at 9 in Figure 4, in the lengthof the strip I, adjacent the edge 4. At such time, preferably, also the strips I are operated upon to' roughen the comparatively smooth surface 3 at such spaced points in the'length of the strip adjacent the edge 4.

To accomplishthe foregoing object, a perforating device of any suitable construction may be caused to act upon the strips I, adjacent the edge 4 thereof, in such a manner that the perforating device enters the strip by first engaging the abrasive surface 2 thereof, and then passing through the fabric, or. other material of the strip to cause said material to break out from the surface 3 to leave protrusions I0, comprising the broken ends of said material extending from the surface 3 to roughen said surface in the region of such protrusions.

The operation upon the'st s in the manner just described results inbrea down the abrasive surface 2 -in the region of the points 9 so as to providean area of said abrasive surface 2 which can be brought into more close adhesive engagement with the surface 3 as the strips I are rolled into their conical formation.

The foregoing operation upon the strips -I also provides a roughened area of the surface 3 of the strips adjacent their edges 4 to which glue or other adhesive will better adhere. I

As the strips I are rolled to their conical formation, glue or other'adhesive is applied tothe surface 3 over an area lengthwise of the strip adjacent the edge 4, as indicated at Il. Some of the glue,'or other adhesive, so applied passes through the perforations, previously provided at the points 9, to insure that a suiiicient amount of glue is applied between adjacent layers of the strip I comprising the conical roll. This produces a tight bonding of such adjacentlayers at the inyner end of the cone provided by the edge 4 of the strip I. By reason of the tight lbonding of the respective layers of the strip at this inner end of the cone, there is provided a comparatively strip along said edge, the adhesive so applied being indicated at IIa.

The mandrel, generally indicated at I2, comprises a shank portion I3 by which the same isl secured to a lathe or drill chuck in the usual manner; al thickened collar portion I4 provided with a tapered screw thread I 5; and a cylindrical bearing portion I6 having a rounded nose lia. In assembling the cone 20 upon the mandrel I2, the cylindrical bearing portion I6 of the mandrel is inserted into' the bore of the cone from the end 4, which end, because of its comparatively unyielding condition provided by the bonding method above described, is enabled to be screwed upon the tapered thread I5 to provide a firm interlocking ccliinection between the cone 20 and the mandrel The working end 1 of the cone 20 extends slightly beyond the nose I6a of the mandrel, and this fact together with thefact that the strip comprising the cone 20 is somewhat loosely coiled, and the layers thereof are not adhesively secured together at said working end 'I, makes said end somewhat yieldable or resilient while at the same time the length of the cylindrical 'bearing portion I6 of the mandrel is such as to provide a desirably suiiicient bearing for the major portion of the length of the cone. l

The foregoing provision, of a bearing portion of the mandrel of substantial length, together with a certain flexibility of the working end of the cone, provide the composite tool with desirable characteristics of capability to be engaged firmly, though yieldably, with the work. Thus. the highest eiliciency of the abrading capacity of the tool isobtained while the yieldability of the Working end enablesvthe same to be exibly maneuvered, and eliminates a tendency to gouge or mar the work under certain conditions which is a characteristic of less flexible abrading tools.

III)

Having thus described my invention, which I claim as new and desire to secure by Letters Paten t of the United States is:'

l. An abrasive element of the class described,

Vcomprising a rolled strip of material, having abrasive applied to one surface thereof, a portion of said abrasive surface being brokenadjacent one edge of said strip, the opposite surface of said strip being roughened adjacent the same edge thereof, and adhesive applied to said latter surface of-said strip adjacent said edge, the overlying' layers of said strip being tightly engaged one upon the other adjacent the edge to which the adhesive is applied when said strip is rolled to form the abrasive element.

2. An abrasive element of the class described, comprising a rolled strip of material, having an abrasive surface and a non-abrasive surface, said strip being perforated adjacent onei edge thereof, whereby to provide broken areas in the abrasive surface adjacentthe points of said perforations, and roughened areas in the non-abrasive surface adjacent the points of said perforations, said strip having an adhesive applied to its non-abrasive surface adjacent the area of said perforations, and said strip being tightly rolled to form a cylinder with adjacent surfaces of overlying portions of said strip at the adhesiveiy treated edge thereof being vtightlyengaged together to provide a firm'bond at one end ot said element adjacent said edge.

3. In an abrasive tool of thec lass described, in combination, a mandrel having a tapered threaded portion, and an abrasive element comprising a rolled strip o! material having abrasive applied to one surface thereof, a portion ot said abrasive surface being broken adjacent one edse of said strip, the opposite suriace 'of said strip being roughened adjacent, the same edge thereof. and adhesive applied to said latter surface o! said strip adiacentsaid edge, the overlying layers ot said strip being tightly engaged together one ixpon the other adjacent said edse when said strip is rolled to `form the abrasive element, said element having a central bore of slightly less diameter than said threaded portion and into which said portion is screwed .for inter-locking 10 connection of said element with saidmandrel.

ALBERT FIELD. 

